Infusion catheter

ABSTRACT

A device and method to dissolve or eliminate blood clots from a patient relies upon a non-rapid moving mechanism to physically dissolve clots without damaging endothelium of the arteries and veins of a patient. In one embodiment, in addition to mechanical agitation of a clot, a thrombolytic agent is administered simultaneously with such agitation. Preferably, intermittent agitation is utilized over a prolonged period of time to effectuate clot removal.

RELATED APPLICATION

This application claims priority from U.S. Provisional PatentApplication No. 60/140,886 filed on Jun. 24, 1999 and is a continuationof U.S. patent application Ser. No. 09/599,987 filed Jun. 23, 2000.

FIELD OF THE INVENTION

The present invention relates to a device and method utilized within themedical field to dissolve or eliminate blood clots that may blockarteries, veins, grafts, implants, stents, catheters, and otherstructures. In one embodiment, pharmacological and mechanical action iscombined to achieve this result.

BACKGROUND OF THE INVENTION

The presence of thrombus, or blood clot, within arteries, veins, grafts,and vascular channels of the bodies is a challenge to many disciplinesof medicine. If the thrombus develops acutely, it may create a medicalemergency. Even if the thrombus develops gradually, conservative medicalmanagement with drugs is frequently less than satisfactory. Surgicalintervention is an alternative, although a costly, and, at times, anineffective one in many cases. Catheter directed thrombolysis iseffective, but time consuming and very costly, because of the expense ofthe drug and the intensive care needed to monitor this therapy. Asuccessful catheter infusion thrombolysis may take 36 to 48 hours toachieve complete thrombolysis.

Mechanical thrombolytic devices have been developed which are quick andeffective in dialysis grafts, mainly because of the nature of such freshunorganized clots presented in such situations, but such devices are noteffective in removing most of the thrombus in arteries and veins of thebody. Many of these mechanical devices have the potential to damage theendothelium of the arteries and veins, as well. The endothelium is afragile covering of the inside of arteries and vessels, and is easilydamaged with mechanical forces. This may cause a cascade of eventsresulting in thrombosis, restenosis, accelerated atherosclerosis,valvular dysfunction, platelet aggregation, late thrombus formation, andother untoward events. By damaging the endothelium during percutaneousthrombolysis, long term patency of the vessel is compromised.

Many mechanical thrombolytic devices have been developed to hasten theprocess of non-surgically eliminating clot from blood vessels, but inmost cases, they fail to remove all of the clot. This necessitates anadditional procedure of protracted infusion of a thrombolytic drug,which is the procedure the mechanical thrombolytic devices were designedto replace.

Mechanical devices exist that also deliver a drug to aid in thedissolution of thrombus, but are utilized and then removed, usually in20-40 minutes. Such methods and devices do provide mechanical actionover a protracted period of time while the drug is being infused. As aresult, there is invariably thrombus remaining at the termination of theprocedure, necessitating the infusion of a thrombolytic drug through adifferent catheter for a protracted period of time to eliminate theremaining clot. This proves costly as more resources in the form ofpersonnel and the expensive drugs are consumed.

The prior art mechanical thrombolytic devices and the prior artcombination mechanical-pharmacologic devices are therefore designed tobe operated mechanically for short periods of time, usually 20-40minutes total, and at very high speeds or frequencies. Prior art devicesare designed to act in short, intense bursts and involve rotatingbaskets and brushes, propellers, water jet, Venturi effect, vibrational,and other mechanical methods. The mechanical action is often effectivein debulking, or lessening, the clot burden, but rarely effective inremoving or dissolving all of the clot. Part of the reason is that aclot adherent to the wall of the vessel is not affected by thesemechanical devices. The use of these devices to perform the incompletemechanical thrombolysis necessitates a procedure which demands theattention and the time of a physician, a nurse, and severaltechnologists in an interventional suite, catheterization lab, oroperating room.

The prior art devices are also expensive, typically costing $500-700 ormore. This tremendous expenditure of time, effort, and supplies isusually not rewarded with complete success, creating a need to placeanother expensive infusion catheter within the clot, transferring thepatient to an intensive observation area, and infusing thrombolyticdrug(s) for a protracted period. The patient is then returned to theinterventional suite many hours later, and most often, the action of thethrombolytic drug has resulted in complete thrombolysis with no residualclot.

The net consequence is that a lot of time, energy, personnel, and moneyare expended with the use of prior art mechanical andpharmaco-mechanical devices, with incomplete results, necessitating theuse of a relatively long infusion to effect complete thrombolysis.Therefore, the use of the prior art devices to dissolve a clot duringthe course of a procedural intervention is unsatisfactory, and anunnecessary consumption of resources. Moreover, the design and speeds atwhich such devices operate risk significant injury to a patient.

The existing mechanical and pharmacomechanical devices also suffer froma design that limits the thrombolytic action to an area near the tip ofthe catheter. This is true of the rotating baskets, propeller typedevices, rotating brushes, water jet, ultrasonic, sub-sonic, vortex, andother mechanical thrombolytic devices. Many of these can be activatedfor only short periods of time, i.e., seconds or minutes, lest theyoverheat or cause hemolysis or blood loss. There is a real potential formany of them to damage the endothelium, or lining of the blood vessels,if used for more than a few seconds at a time. Moreover, thepharmacomechanical devices have apertures for injecting the thrombolyticdrug near the tip of the catheter as well. While these designs may besatisfactory for a short segment occlusion of 10 cm. or so, frequentlythe occlusion because of thrombus is much longer. Such prior art devicesmust be advanced and retracted within the lumen of the occluded vesselto “treat” one segment of the vessel at a time, usually resulting inincomplete and ineffective treatment of the entire occluded segment,thus requiring the need for the patient to undergo a prolonged infusionof the thrombolytic drug with the attendant increase in costs.Typically, the thrombus within the deep venous system of the leg needinginterventional therapy extends from the calf veins to the inferior venacava, a length of 40-60 cm. Femoral-popliteal arterial grafts are 30 cm.or so.

There are many prior art devices for the treatment of thrombus or bloodclot within the arteries and veins of the body, as the occurrence ofblood clots is a common and serious medical condition. The trend towardlesser invasive procedures has benefited patients in improved outcomes,less morbidity, and without the need for surgery. There are many priorart catheters designed for infusion of lytic agents, such as urokinaseand tissue plasminogen activator substance (tPA). Representative ofthese are U.S. Pat. Nos. 4,968,306, 5,250,034, 5,267,979, 5,624,396,5,782,797, and 5,425,723. The process of infusion and dissolution of thethrombus is a lengthy one, taking 24 to 48 hours frequently. The lyticagent bathes the thrombus and pharmacologically dissolves the thrombusover time. Such methods necessitate the use of a large amount ofexpensive drug or lytic agent and overnight monitoring in a criticalcare unit. The process may cost upwards of $20-30,000.

Purely mechanical thrombolytic devices were developed as an alternativeto infusion thrombolysis. These devices attempt to dissolve the clot ina relative short procedure, usually less than an hour. Representative ofthese are U.S. Pat. Nos. 4,747,406, 4,923,462, 5,569,275, 5,397,293,5,766,191, and 5,997,558. While they may be effective in removing alarge amount of the thrombus in a relatively short period of time, thereis usually incomplete thrombus removal necessitating further infusion oflytic agents to dissolve the residual thrombus. Moreover, they removeenough of the clot so that partial flow may be reestablished within thevessel, causing the lytic agent to be washed out of the clot containingvessel as it is being infused.

Combination devices which utilize mechanical thrombus disruption andpharmacological agent infusion are represented by U.S. Pat. Nos.5,279,546, 5,197,946, 5,362,309, 5,279,456, 5,725,494, and 5,713,848.These combination devices are an improvement, in that they attempt toutilize a lytic agent and mechanical motion of various types to disruptthe clot. They however, are time inefficient and the action of the lyticagent usually takes hours to achieve complete thrombolysis. All of theprior art combination devices are used within the confines of aprocedural intervention that takes less than an hour and would damagethe endothelium if used for more protracted periods of time. Many wouldoverheat or fail, as the mechanical motion demands high frequencyvibrations or rotation. Even Dubrul, U.S. Pat. No. 5,731,3848 at thelowest frequency of one vibration/second, would damage the endotheliumif activated for several hours.

There is a dichotomy in the design of all of these prior artthrombolytic catheters. The pure infusion catheters only passively bathethe clot and have no method of increasing the surface area of the clotto be dissolved. They demand very protracted infusions to clear theclot. The purely mechanical devices diminish clot burden, at a cost oftime, materials, and personnel, but frequently leave significantresidual clot requiring a prolonged infusion. The combinationpharmaco-mechanical devices attempt to fragment the clot and deliver thelytic agent simultaneously, but are only able to be mechanically activefor short periods of time, usually not enough time for the lytic agentto dissolve the clot.

Therefore, there is a need for a device which provides a mechanicalaction to increase the surface area of the clot for efficaciousdissolution by the lytic agent, provides this mechanical action for aprolonged period of time while the lytic agent is acting, provides amechanical action which is not harmful to the endothelium of the vessel,and is time efficient for the operator and the patient.

SUMMARY OF THE INVENTION

The device of the present invention differs from all of the prior artdevices in that it provides a mechanical means of gradually disruptingthe clot as the lytic agent is acting, usually over a few hours. Itovercomes the problems of potential mechanical failure or endothelialdamage which would occur should the other pharmaco-mechanical devices beused over a period of several hours. It overcomes the problem of tryingto dissolve some of the clot with an expensive mechanical device and allof the attendant problems listed above. It overcomes the problem ofextremely protracted passive infusion thrombolysis.

The device of the present invention obviates the need for the abovedescribed prior art procedural interventions and use of prior artdevices by providing a device which is simply placed into the clot orthrombus, and the intermittent mechanical action and continuous orintermittent infusion of lytic agent occurs, preferably, after thepatient has been transferred to the observation area. As more completelydescribed below, the present invention saves the step of intensemechanical intervention, saving costs in time, personnel, and materials.The present invention also lessens the time and the amount of drugneeded for thrombolysis when compared to standard non-mechanicalinfusion thrombolysis.

The present invention satisfies the long-felt, but unsolved need for apharmacomechanical thrombolytic device that will be effective overlengths of vascular veins and arteries and which can be utilizedcontinuously, or intermittently, over several hours to allow thethrombolytic drug to be completely dissolve the thrombus. The mechanicalcomponent of the present invention disrupts the clot and provides moresurface area for the thrombolytic drug to act upon.

Accordingly, it is one object of the current invention to solve theproblems experienced in using prior art devices and methods by providinga device that is mechanically active over a substantial length of thecatheter while allowing the thrombolytic drug to be infused or injectedover the same substantial length of the catheter. It is also an objectof the present invention to permit synergy of the mechanical andpharmacologic actions over a prolonged period of time, i.e., up toseveral hours, without damaging the endothelium of the vessel containingthe clot. It is an object of the current invention to combine twoelements: 1) pharmacomechanical device having a working lengthsufficient to span most or all of the length of a clot, and 2) provisionof means to allow the pharmacomechanical action to occur over aprotracted time period. Another object is to create cost efficiencies bydiminishing the time and amount of drug to realize thrombolysis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a depiction of a prior art thrombolytic catheter.

FIG. 2 is a depiction of a prior art pharmacomechanical thromblyticdevice. The brushes near the tip provide the mechanical disruptiveaction and one or two side holes immediately proximal to the brushesallow infusion of the thrombolytic drug.

FIG. 3 is a depiction of the distal tip of a prior art mechanicalthrombolytic device showing a propeller blade used to create a vortexwhich disrupts a clot.

FIG. 4 demonstrates the major arteries of the body, with the rightsuperficial femoral artery representing thrombus prior to catheterdirected thrombolysis.

FIG. 5 demonstrates the major veins of the body, with right iliofemoralvenous thrombosis prior to catheter directed thrombolysis illustrated.

FIG. 6 represents the catheter device of the present invention enteringthe left common femoral artery directed into and through the thrombosedartery in FIG. 4, the mechanically active segment and the infusionsegment span the entire length of the clot.

FIG. 7 represents the catheter device of the present invention enteringthe right popliteal vein and the pharmacomechanical active segmentspaning the entire length of the clot.

FIG. 8 demonstrates a deformable mesh braid of an occluding element inan undeployed, longitudinal, tubular orientation, and showing the innercore and the outer surface of the wire.

FIG. 9 demonstrates the occluding element comprising mesh braid in adeployed radially expanded state. The element occludes the lumen of thevessel and prevent the thrombolytic drug from being washed away from thearea of the thrombus. It should be noted that the outer or inner core ofthe wire may be of varying stiffness, i.e., stiff proximally and limberdistally, to facilitate the mechanical action of the device. Also theoccluding element may be used as a tensioner to facilitate themechanical action, and as a clot dragger to remove residual thrombus.

FIG. 10 is a representation of the device demonstrating, from left toright, the drive motor with the controller incorporated, a “Y” adapterto receive the line from the drug infusion pump, the outer sheath toprevent the proximal portion of the catheter from being mechanicallyactive, the mechanically active segment of the device containinginfusion apertures, and the occluding element. The arrows indicatemotion of the mechanically active segment. Preferably the mechanicallyactive segment of the device contains only one lumen which will housethe guide wire of the occluding element and allow the thrombolytic drugto be infused. The wall of the device may incorporate braided wires orother stiffening material to facilitate the mechanical action.

FIG. 11 illustrates the mechanically active segment with the infusionapertures present within the popliteal, femoral, and iliac veins of apatient. The occluding element is deployed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The current invention may take any one of several forms, but thepreferred embodiment is that of a catheter (hereinafter meant togenerally refer to any guide wire, infusible wire, or similar conduit)which is capable of delivering a thrombolytic agent and creatingmechanical disruption of the clot while the thrombolytic agent is beingdelivered. The mechanical motion or mechanical action can take one ofseveral forms which are described below. The mechanical motion isintermittent and more gentle than prior art devices to prevent hemolysisand endothelial damage. The mechanical motion is slower (e.g., less than200 rpm, more preferably less than about 600 rpm, and most preferablyless than about 55 rpm) than prior art devices and the mechanical motionoccurs intermittently, at preselected intervals. The mechanical actionis therefore of a non-rapid type which can be adjusted for differentslow speeds. As an example, the mechanical action may be activated fortwo seconds and then inactive for five minutes, activated for twoseconds and then inactive for five minutes, and so on until thrombolysisoccurs. Various factors influence the choice of the parameters of speedof action (rpm's or cycles/sec), time of activation, time ofinactivation, total treatment time (time of activation plus time ofinactivation), repetition time, as well as the infusion rate of thelytic agent. These factors include the location of the clot, as moreaggressive thrombolysis with rapid speed of action, longer activationtimes and shorter inactivation times can be achieved within grafts asthere is no concern of damaging the endothelium. However if the thrombusis within a native artery or vein, the speed would be slower, time ofactivation shorter, and time of inactivation longer to keep fromdamaging the endothelium. The age of the clot or thrombus is a criticaldeterminant in the total treatment time, as fresh or subacute clot(hours to a few days) will dissolve more quickly and easier than a clotwhich has been present for longer than 10 days or so. The size of theclot also is a determinant in the choices. A less aggressive (shorteractivation times) and shorter total treatment time is chosen for arelatively small clot of recent vintage. The parameters for the lytictherapy infusion may be varied as well depending on the site, age ofthrombus, size of thrombus, etc. Therefore, the preferred embodiment andpreferred parameters may be site specific.

Generally, the device of the present invention comprises an infusionpump which infuses the lytic agent at a continuous selected rate. Thedevice of the present invention is simply placed into the clot and thepatient sent to an observation area where the lytic agent and mechanicalaction occur. The interventionalist, team, and suit are free to performother cases while the intermittent mechanical action and lytic agentinfusion are being achieved.

In one alternative embodiment, the lytic agent is infused intermittently(e.g., over a period of minutes, such as every 5-15 minutes, or evenlonger time periods, such as every ½ hour, etc.). The mechanical actionmay be selected from a range of 0.1-600 rpms with activation times ofabout 0.1 second to about 60 seconds, and inactivation times of 5seconds to 20 minutes. Typically, the parameters chosen for a relativelyfresh long segment lower extremity venous thrombus are: a) continuousinfusion of the lytic agent, b) mechanical action speed of about 55rpm's, c) activation time of at least about 3 seconds, and d)inactivation time of 3 minutes. Preferred parameters for a long segmentarterial occlusion are: a) continuous infusion of the lytic agent, b)mechanical action speed of action speed of about 30 rpms (0.5cycle/sec), c) activation time of at least about 2 seconds, and d)inactivation time of at least about 3 minutes. A preferred parametersetting for a graft is: a) continuous infusion of the lytic agent, b)mechanical action speed of about 300 rpms, c) activation time of aboutabout 5 seconds, and d) inactivation time of about 1.5 minutes. Ofcourse, as discussed above, the clinical setting and patient conditionmay require alternative parameters, and the above are suggested only asexamples.

Intermittent action provides for relatively long periods of nomechanical action in which the endothelium is not contacted, scraped, ordamaged. The slower action of 30-55 rpm's (less than 1 cycle/second) andthe short activation times of 2-3 seconds prevents abrasion and damageof the endothelium as well. It is the intent of the current invention toprovide a time of inactivity which is at least as great, and preferablysubstantially greater, than the time of activity of the device. Thisserves to protect the endothelium, but also creates an environment foraccelerated thrombolysis by the lytic agent. The slower speed of themechanical action along with the very short activation times withrelatively long periods of inactivation allows the mechanical action tocontinue for at least several hours while the lytic agent is acting todissolve the clot. As an example, if the total treatment time is threehours, and a mechanical action speed of 30 rpm's is used with anactivation time of 2 seconds, and inactivation time of 3 minutes, atotal of only 60 cycles of mechanical action would occur in the entiretreatment. This will be sufficient to create the environment foraccelerated thrombolysis, but not sufficient to cause endothelialdamage.

The endpoint is resolution of the clot, which will vary from patient topatient, location to location, and depend on the age and size of theclot amongst other factors. Typically, however, a total treatment timeof about one to three hours is anticipated to lyse fresh venous andarterial thrombus with the above techniques, although total treatmenttimes of about 30 minutes to about 36 hours are generally anticipated.The slower, intermittent mechanical action of the device augments theaction of the lytic agent by enhancing admixture of the lytic agent andclot, by creating more surface area within the clot, and by mechanicaldisruption of the clot, while avoiding damage to the endothelium.

Alternative embodiments include a catheter (preferably a singlecatheter) with just a means to create the mechanical action, without anymeans to treat the thrombus pharmacologically. Another embodiment allowsthe infusion of the thrombolytic agent after the mechanical portion isactivated. Both the mechanical and the pharmacological delivery elementspreferably are effective over a substantial length of the catheter,rather than just concentrated at the tip, as is the case with prior artdevices.

The mechanical element may be one of several types, i.e., ultrasonic,vibrational, rotational, bi-rotational, longitudinal motion, expansile,and the like. A suitable mechanical element may be a wire or a smoothwall catheter, have apertures for the injection of the thrombolyticagent, or projections from the side of the device to better disrupt thethrombus. A preferred embodiment uses wave like undulations orvibrations to disrupt the clot slowly while the pharmacological agent isbeing infused. Since the mechanical motion is intended to be used forsome protracted period of time, it is advantageous for the mechanicalmotion to be one which does not promote hemolysis nor damages theendothelium. A slower motion rather than a rapid motion is thereforedesirable.

In one embodiment, a motor that causes the catheter to vibrate orundulate is attached to a wire that is inserted within a lumen of thecatheter or to the catheter itself. Braiding within the wall of thecatheter to enhance transmissions of the vibrations may be utilized, andthis may obviate the need to insert a wire within the catheter. A stiffsegment of the catheter proximally is desirable, as the efficiency oftransmitting the vibrations from the motor to the mechanical elementsegment is then enhanced. One may compare this stiffer or more rigidproximal segment to a fly rod transferring energy to a fly line or thehandle of a bullwhip causing the action of the whip. Again, it is theintent that a substantial length of the intravascular portion of thecatheter is provided with the mechanical action.

A separate sheath component through which the device is inserted may beused to keep the entire device from being mechanically active. In thiscase, the outer sheath houses a proximal portion of the device and themechanically active portion of the device extends distal to the tip ofthe outer sheath. In one embodiment, the catheter, at least in themechanically active segment, contains only one lumen, although more thanone lumen is feasible.

Another method to accomplish an effective mechanical motion is to placetwo wires in a catheter wall so that they are disposed on opposite sidesof the lumen. The wires are moveable within the catheter wall proximallyand affixed at a point at which the mechanical motion is to begin. Analternating to and fro motion of the two wires causes the catheter toundulate distal to the fixation point. A motor provides the desiredmotion of the two wires.

Still another method of effective mechanical motion involves a catheterhaving a spiral shape in the distal desired length. Such a catheter isstraight proximally, but of a spiral configuration in the desiredmechanical element segment. A motor causes the catheter to spin at arather slow rate (approximately one to 300 times per minute). Theproximal portion, because it is straight, does not have any substantialmechanical disruptive motion. The distal portion, because of the spiralconfiguration, spins in a corkscrew manner against the clot or wall ofthe vessel, disrupting the clot.

Where the catheter includes a guide wire to stiffen it, and where alytic agent may be infused through side holes, the guide wire may byspiral shaped as well. A guide wire with a removable inner straightmandrel and an outer cylinder of shaped memory alloy may be utilized tocreate the spiral or corkscrew configuration. When the inner mandrel iswithin the outer sleeve or cylinder of the guide wire, the guide wire isstiff and more or less straight. When the inner core is removed theguide wire assumes a spiral configuration causing the infusion catheterover it to also assume a spiral or corkscrew configuration.

A variation of the above entails rotating the spiral catheter one wayand then the other, similar to an agitator in a washing machine. A motoris provided to effect such motion. Yet another modification involves aserpentine or other shape to the catheter. Any motion can be employedwith any different shape. Complex motions, such as a longitudinal wavelike motion of the catheter combined with axial rotation, may beadvantageous.

In another embodiment, an intermittent motion of the catheter isprovided by a pump that delivers lytic agent forcefully in programmablepulses. Such a pump is commercially available (AngioDynamics,Queensbury, N.Y.). It generates abrupt pulse waves which cause the lyticagent to be sprayed into the thrombus through side holes in thecatheter. Generally, the connecting tubes dissipate the motion causedwhen this abrupt and forceful pulse of medicine occurs. By more rigidlyconnecting the Pulse-Spray pump to the device of the current inventionand preventing the dissipation of the pulse wave forces in theconnecting tube, the pulse wave forces are transferred to the device ofthe current invention, causing it to move within the body. Theconnecting elements may be made of steel or any other rigid substancethat is capable of transferring the forces from the Pulse-Spray machineto the catheter efficiently so that the catheter is mechanically activeas described above. Since the frequency and duration of pulses areprogrammable on the pump, a separate motor to move the catheter will notbe needed. Alternatively, a flexible catheter may be provided which isserpentine or spiral in shape. The pulse of the Pulse-Spray pump willstraighten the catheter from its original shape, causing desired motionwithin the clot while the lytic agent is being dispersed.

An intermittent motion may be provided to any of the embodiments, i.e.,so that the mechanical motion is activated every few seconds, every fewminutes, or for any given time period. In fact, this is desirable toprevent damage to the vessel endothelium, but allows for enough clotdisruption to enhance the action of the thrombolytic agent. The presentinvention is intended to provide a slow, intermittent motion overseveral hours to allow a lytic agent to work completely while notdamaging the endothelium. Of course, the device may employ mechanicalmotion without the addition of a thrombolytic drug. Therefore, thecurrent invention differs from prior art devices in many respects,including shape, length of mechanically active segment, the rapidity ofthe motion, the programmability of the motor drive, shorter periods ofactivity, longer periods of inactivity, the ratio of periods ofinactivity to periods of activity, the number of total cycles ofmechanical action during a treatment, as well as other featuresdescribed herein.

In one embodiment, a catheter is constructed with multiple apertures(side holes, slits, or other openings) through which a thrombolyticdrug, when utilized, is injected or delivered. A separate pump controlsthe rate and duration of drug administration. The apertures arepositioned throughout the mechanical motion segment of the catheter,which may include much of the body of the catheter in addition to thearea near the catheter tip. The apertures preferably occupy about 20-60cm. of the distal aspect of the catheter, rather than the typical distal10 cm. of other prior art devices, although the apertures may occupyfrom 5-60 cm. of the distal aspect of the catheter.

The motor which drives the mechanical portion of the device aretypically different than those of the prior art, which are designed tobe utilized for a short time during a procedure and are typically handheld devices with a finger activation, which rotate at very high rpm's.The motor of the current invention may be programmable to rotate atslower rates (about 0.1-600 rpms) over much longer periods of time (30minutes-days.) In a preferred embodiment, the motor may be programmed torotate, or have other mechanical action, at a mechanical action rate, orspeed, of about 0.5 to 55 rpms and a total treatment time of about 30minutes to 5 hours. The activation times may vary from about 0.1-60seconds and the inactivation times may vary from about 5 sec to 20minutes in the preferred embodiment. The program may contain anintermittent mode in which there would be no motion provided by thecatheter for specified periods of time. A motor controller, which isprogrammable, may be incorporated into the motor or may be separate. Themotor housing is designed to accompany the patient to the ward orcritical care unit so that it can be monitored while thepharmacomechanical thrombolysis proceeds. A battery and/or electricalconnections are provided.

Another aspect of the present invention relates to an element whichoccludes a vessel distal to the catheter or, at least, distal to themechanical and pharmacologic segments of the catheter. This occludingelement can take any one of several forms, including an inflatableballoon, a deformable mesh braid with a membrane, a malecot with amembrane, or other suitable configuration. A preferred embodimentconsists of a deformable mesh braid mounted on the outer surface of amovable core guide wire. When the inner core is retracted in relation tothe outer surface, the braid changes from a longitudinal tubularstructure to a radially expanded disc like structure which occludes thelumen of the vessel. The membrane covers or is disposed in theinterstices of the braid. The wire is preferentially inserted throughthe catheter and may or may not be designed so as to assist in themotions of the catheter described above. A primary purpose of thiselement is to keep the pharmacologically active thrombolytic drug fromwashing out of the area of the clot once some of the clot has beendissolved. The prior art infusion catheters frequently are effective inrestoring a channel within the clot, but subsequently the thrombolyticdrug is washed away from the clot secondary to the success ofre-establishing flow. Further thrombolysis is the result of a systemiceffect of the drug, rather than the desired local drug delivery of theinfusion catheter. This situation necessitates longer infusion timesutilizing more expensive thrombolytic drugs. This translates into addedcosts to achieve complete thrombolysis. The occluding element of thecurrent invention would prevent the washout of the thrombolytic drugfrom the thrombus, accelerating the thrombolytic process. Protectionagainst embolization is a secondary purpose.

Balloons have been used for greater than 30 years to temporarily occludevessels. Filters are included in more recent prior art to protectagainst distal embolization, but the occluding device of the currentinvention, in the form of a malecot or deformable mesh braid containinga more or less impermeable elastomeric membrane, has not been utilizedbefore.

Therefore, the foregoing description details a unique device and methodthat creates time and cost efficiencies in removing thrombus from thevascular channels of the human body. The device differs from prior artin addition to those previously listed features, in: 1) the length ofthe mechanically active segment, 2) the distribution of the aperturesfor drug insertion when combined with a mechanically active segment, 3)the configuration and programmability of the motor drive, 4) thepresence of a motor controller, 5) the distal occluding element, 6) needto move the mechanically active segment within the clot (prior art), and7) the inclusion of a combination of these features within one device.The device and method of the current invention also differs from priorart in that it expedites long segment thrombolysis, something that hasnever been achieved with prior art devices. The present inventionprovides for a short interventional procedure to place the device, begininfusion and initiate desired mechanical action. When the patientreturns in one to several hours, the thrombolytic process is complete,the device can then be removed, and patient discharged shortlythereafter.

The present invention is preferably used to clear long segmentocclusions secondary to thrombus within arteries, veins, and grafts. Inthe case of iliofemoral deep venous thrombosis (clot involving theiliac, superficial femoral, and popliteal veins), a preferred procedureis to percutaneously enter the popliteal vein via a Seldinger approach,insert a multipurpose angiographic catheter, and inject a small amountof contrast medium centrally. This will determine the extent of thethrombus in the iliac vein. The initial catheter is then exchanged forthe device of the current invention that is positioned so that themechanically active segment, and the aperture containing segment, spanthe entire length of the clot. The lengths of these segments are chosenfrom one of several different models of the device so that the length ofthe active segments matches the length of clot within the patient. Ifdesired the distal occlusion element may be deployed at this time, oreven before the catheter device of the invention is inserted. Themechanical portion of the catheter is connected to the drive motor, andthe infusion lumen is connected to the drug infusion pump. Appropriatedesired frequencies, actions, motions, pauses, etc., are programmed intothe drive motor controller, and the motor initiated. The flow rate ofthe thrombolytic drug is selected and the drug infusion pump is begun.The patient is then transferred to a holding area, hospital room, orcritical care unit for observation. The thrombolysis may be monitored byduplex compression ultrasound, but eventually the patient will return tothe interventional suite to be evaluated with contrast injection,usually within three to five hours.

In the case of superficial femoral artery thrombosis or femoropoplitealbypass graft occlusion from thrombus, either the ipsilateral femoralartery or contralateral femoral artery may be entered by Seldingertechnique. A contrast agent is injected to determine the extent of theclot, and the appropriate device of the invention is chosen to match thelength of clot within the patient. It is positioned, with or without thedistal occlusion device, so that the mechanically active andpharmacologically active segments essentially span the entire clot. Theconnections are made as above, and the appropriate parameters chosen andprogrammed. The mechanical segment and the pharmacological segment areinitiated. The patient is then handled as in the prior paragraph. Anendpoint is reached when pulses are detected clinically, or when thepatient is returned to the angiography suite to be restudied. Anyresidual debris within the vessel may be aspirated before removing thedistal occlusion device.

In addition to the description and guidance provided herein, the presentinventor provides additional written description and enablement supportfor the present invention by incorporation by reference of U.S. Pat.Nos. 5,279,546 and 5,569,275.

It is obvious that variations of these methods may be employed toachieve the same desired effect. It is understood that variousmodifications of the device of the current invention and method may beaccomplished within the scope of this invention.

1. A pharmomechanical device, comprising: a catheter having a spiralshape throughout its length that is substantially incapable of damagingan endothelium of a vascular structure, said catheter rotating between30 rpm and 600 rpm once it is inserted inside a patient, said catheterincreasing the surface area of a clot in said vascular structure suchthat said clot can be dissolved by a lytic agent; and means forproviding a rotational motion to said catheter.
 2. The device as setforth in claim 1, further comprising a pump that delivers lytic agent inpulse waves, said pulse waves causing an intermittent mechanical motionof said catheter, and wherein an intermittent mechanical motion of thecatheter is caused by the delivery of said lytic agent.
 3. The device asset forth in claim 2, wherein said pump is programmed to deliver saidlytic agent at a desired frequency or duration.
 4. The pharmomechanicaldevice of claim 1, wherein said catheter rotates at less than about 55rpm.
 5. A pharmomechanical device, comprising: a catheter having alength and having a spiral shape throughout a substantial portion ofsaid length, said catheter being substantially incapable of damaging anendothelium of a vascular structure, said catheter rotating at less thanabout 600 rpm once it is inserted inside a patient to increase thesurface area of a clot in said vascular structure; and a means forrotating said catheter.
 6. The device as set forth in claim 5, furthercomprising a pump that delivers lytic agent in pulse waves, said pulsewaves causing an intermittent mechanical motion of said catheter, andwherein an intermittent mechanical motion of the catheter is caused bythe delivery of said lytic agent.
 7. The device as set forth in claim 6,wherein said pump is programmed to deliver said lytic agent at a desiredfrequency or duration.
 8. The pharmomechanical device of claim 5,wherein said catheter rotates at less than about 55 rpm.
 9. Apharmomechanical device, comprising: a catheter having a spiral shapethroughout substantially its entire length that is substantiallyincapable of damaging an endothelium of a vascular structure, saidcatheter rotating less than about 55 rpm once it is inserted inside apatient, said catheter increasing the surface area of a clot in saidvascular structure such that said clot can be dissolved by a lyticagent; and a pump that delivers lytic agent in pulse waves, said pulsewaves causing an intermittent mechanical motion of said catheter. 10.The device as set forth in claim 9, further comprising a pump thatdelivers lytic agent in pulse waves, said pulse waves causing anintermittent mechanical motion of said catheter, and wherein anintermittent mechanical motion of the catheter is caused by the deliveryof said lytic agent.
 11. The device as set forth in claim 10, whereinsaid pump is programmed to deliver said lytic agent at a desiredfrequency or duration.
 12. The pharmomechanical device of claim 9,wherein said catheter rotates at less than about 55 rpm.